NEW YORK — Brian Cashman sat in front of a microphone on Tuesday afternoon for one of the many typical tasks that come with being general manager of the Yankees. About 90 minutes after the 4 p.m. nonwaiver trade deadline elapsed, he walked through the rationale of his recent moves, which included no blockbusters.

But before Cashman could discuss his latest acquisition — Monday’s trade for Lance Lynn — a prime example surfaced of why he’d made it in the first place. Cashman began his session confirming that recently acquired lefty J.A. Happ was sent home with a mild case of hand, foot and mouth disease, the same ailment that has sidelined the Mets’ Noah Syndergaard. It’s unclear how Happ contracted the condition.

“Yeah, how about that?” a bemused Cashman said, in his first public comments since trading for Lynn, which turned out to be his final move before the deadline.

The Yankees will stash Lynn away in the bullpen though he has been a...